Leg resistance training: Effects upon VO₂peak and skeletal muscle myoplasticity

The central focus of this review was to determine whether concurrent heavy loaded leg strength exercises and reduced aerobic loading influence VO ₂ max or predicted VO₂ max when measured on a cycle ergometer or treadmill or both. Our review indicates that measurement of VO ₂ max, time to exhaustion, and the type of physical training program employed may influence endurance capacity on a cycle ergometer or treadmill or both. Heavy resistance training (80% of 1 RM) can induce shifts in myosin heavy chain (MHC) isoforms from type IIb (glycolytic) to type IIa (mixture-oxidative/ non-oxidative) in trained peripheral muscle. The precise mechanisms causing these increases in aerobic capacity still remain unresolved in the literature. These peripheral adaptations may be attributed to concurrent heavy loaded-high volume (3 sets of 12 to 16 repetitions performed to volitional fatigue) leg resistance training and reduced volume aerobic loading. The mechanisms responsible for this change may be associated with the cross sectional area of the trained musculature. For example, if the cross sectional area of oxidative and glycolytic skeletal muscle increases, even in the same percentages of the original muscle mass, then any work rate will represent a lesser percentage of that muscle's maximal capacity to complete both oxidative and non-oxidative work.